If gear is raised after takeoff with a flashing master warning and thrust reverser ARM annunciators, what is the probable cause?

• A. Hydraulic failure
• B. Failure of one or both landing gear ground safety switches
• C. Electrical system fault
• D. Speed brake jam

Answer: (B)

The warning logic in the Beechjet uses the landing gear ground safety switches to confirm when gear is fully up and retracted. If one or both of these switches fail, the system can wrongly sense that the gear isn’t up, even though it is, causing a master warning to flash. The thrust reverser arm annunciators can also be affected by interlock circuitry tied to gear position, so a fault in the ground safety switches can trigger those indicators as well. This combination of annunciations is most directly explained by a failure of the landing gear ground safety switches, rather than a hydraulic problem, a general electrical fault, or a speed brake issue, which would produce different symptoms.